Powder Temp sensitivity - extreme cold

[locknloader]

About to start loading up some .223 and was wondering what some powder choices may be that are stable across cold temps? I was reading H4895 was a good choice for my intended purposes.

Will be used for plinking in AR's exclusively, it's extremely cold here right now (around 0*f, colder with wind chills) so i want to make sure i get something that will be stable once it warms up. I don't know much at all about this subject, just stumbled across it so want to make sure i get a basic understanding of how temperature affects the rounds.

If i load a bunch now around 0*f, what kind of variance should i expect when it warms back up to tolerable levels (50-90*f)?

 

[m&p45acp10+1]

IMR 4166 is supposed to be less temp sensitive. For 55 grain bullets it requires a compressed load. I loaded some up in my AR it gave consistent groups of abput 1 to 2 moa at 50 yards with irons. Which is about as about as good as it gets with me using irons. My Savage gave sub 1inch at 100 from a bench rest.

 

[RC20]

Your powder is not subject to wind chill.

Ergo, if its zero, then zero is what the cartridge and the gun experience.

Only organic entities (you) are subject to wind chill, inanimate object (powder, guns, cartridges) are not

Granted you may not shoot well as a result due to the impact on yourself and as your are plinking, likely not at all.

Frankly for an AR, I doubt that has any real impact accuracy wise other than it may not function unless you have synthetic lube in the gun (Mobil 1 works)

The real issue with temp stability is on the upper end when it gets more energetic and potentiality over pressure.

At low temps you just slow down the bullet, it could theoretically drop out of the node for accuracy due to velocity decrease but unless its calm, shooting in the wind at zero is not a good bench rest environment!

 

[Don Fischer]

About the only time I do much reloading during the really cold time's, is when I already have a load worked up in better weather. I will work up loads as cold as 40* outside and the high end of that is 79*. I have never experienced a problem with temp change that I'm aware of. I get the idea reading threads like this that people seem to think that if they develop a load in 90* weather, 91* will blow the thing up. What happens if they develop the thing in in 20* weather and shoot it at 19*? I would not develop a load at 20* and expect it to work well at 110*! Haven't a clue what might happen! Late spring and mid fall are great time's to develop loads! Then if you need loads at other time's, just load them

EDT: Just occurred to me. Wonder how ammunition maker's work around temp difference's?

 

[locknloader]

@ Don Fischer, they likely have a climate controlled facility, i'm sure the people running the presses would not enjoy outside winter temps!

I realize that slight temp variation should not matter, but since we are talking about making load around 20*f, then possibly shooting them again in the summer when its 90*f, thats a pretty massive swing.

Sounds like i should just load up enough for each range session and save the bulk loading for warmer days.

 

[jmr40]

I can't help with 223 specific loads. Just to add that typical powder changes 1-3 fps for each degree temperature changes. Develop a load at 70 degrees and shoot it at -20 and you'll see 90-250 fps less speed at the muzzle.

That is a 90 degree temperature swing and more than most of us will see. But even with those extremes 250 fps at the muzzle doesn't make a huge difference at ranges under 200 yards.

The better powders will only see a change of about 1/2 fps difference per one degree of temperature change, so call it a max of 45 fps for the same 90 degree temperature change. All things being equal I'll pick a powder less sensitive to temp swings if given the choice. But realistically it isn't usually that big of a deal. I'd still use the powder that was most accurate.

If you're developing loads in cold weather you should still be OK as long as you stay within the manuals specs. A max load my have a claimed velocity of 2800 fps at 70 degrees. But at -20 it may well be closer to 2600 fps. If you go over the book loads and get it to 2800 fps at -20, then you may well have a problem at +70

 

[Unclenick]

I would suggest reading this article before anticipating your needs on this topic.

 

[Hanshi]

One of my favorite and most used powders is IMR3031. I've never lived, up until now, anywhere that is routinely "cold". My .350 Rem Mag rifle gives a handloaded 200 grain Hornady a velocity of a little over 2700 fps. Recently in WV at a range this favorite load gave around 50 fps less velocity than it did in Georgia. I've never chronographed any other loads/powders at varying temperatures.

 

[Ifishsum]

Has nothing to do with the temperature when were loaded at, but the temperature a given load is tested at. For instance an upper end load that tests good with no pressure signs when fired at 20 degrees might be too hot when fired at hot summer temps. I think it makes much more of a difference leaving ammo in a hot car or left in the sun than the actual ambient temp but the general advise is to be careful in hot temperatures with a load that was developed and tested at cold temperatures.

Certain powders (primarily ball type) can be harder to ignite at low temperatures which is one reason magnum primers are often recommended with ball powders. And then a load should be developed and tested with those magnum primers from the beginning, rather than simply substituting them for cold weather use of a load previously developed without them.

 

[JeepHammer]

Pulled my rifle out of a -5*F truck yesterday morning and popped a coyote at 360 yds just about daylight.
Did the same thing the day before at -3*F the morning before, but at about 275 yds.
Benchmark on top of CCI small rifle primer, 55 grain Hornady V-max on top.
(Chicken thieving varmints)

I'm perfectly aware that two rounds in Sub-Zero cold doesn't prove a thing, but this same load, both with CCI & Winchester primers works fine for me in +100*F weather and Sub-Zero weather.
At around 80*F this load shoots dime & nickel size 10 shot groups out of my old rifle.
I said 10 shot groups, not 3 or 5 shot groups...

I've put down half a dozen coyotes since this cold snap started, 250 to 375 yards, all one shot kills, rifle shooting on the summertime ballistics tables.
I have to say I'm liking the Benchmark over Varget or 748 Winchester right about now...
Varget works better in the .308, Benchmark in the .223

 

[Mobuck]

"Will be used for plinking in AR's exclusively, it's extremely cold here right now (around 0*f, colder with wind chills) so i want to make sure i get something that will be stable once it warms up. I don't know much at all about this subject, just stumbled across it so want to make sure i get a basic understanding of how temperature affects the rounds."
The temp stability issues may involve working up loads at a specific temp and then using them at a significantly different temp. Has nothing to do with what the temperature is when the ammo is loaded. Other issues may surface related to the brisinance of primers or the ignition of powders in EXTREME cold temps.

 

[Tsquared]

This thread is very timely. Once again Uncle Nick has the answer.

I have been working up a six8 load and the only opportunity to test the load it was 33 degrees outside. The powder is AA2200 and it has a reputation for being temp sensitive. My top end load that is very accurate will probably blow the primer at 90 degrees. I am waiting for a day in the 60's to try my test again.

 

[Colorado Redneck]

Was looking for temperature sensitivity data

And found this on another forum:
(* means degree F) Can't recall which forum, might be Long Range Hunting. Varget seems to be one of the most stable temp wise.


HS-6 1.21fps per *
H110/W296 1.24 fps per *
Imr4227 1.17fps per *
Lil' Gun 1.31 fps per *
RL10x .71 fps per*
Benchmark .44 fps per *
Imr3031 .73 fps per *
Imr8208xbr .59 fps per *
H4895 .23 fps per *
Alliant Varmint pro .89 fps per *
Alliant AR comp .77 fps per *
Varget .19 fps per *
W748 1.32 fps per *
Imr4064 .53 fps per *
Ramshot Tac .91 fps per *
Imr4895 .87 fps per *
AA4064 1.11 fps per *
AA2520 .98 fps per *
RL15 1.52 fps per * from 50* and up
PP2000MR .99 fps per *
Imr4320 1.32 fps per *
Ramshot Biggame .98 fps per *
H380 1.44 fps per *
VV N150 1.08 fps per *
H414/W760 1.42 fps per *
Imr4350 .64 fps per *
AA4350 .47 fps per *
H4350 .29 fps per *
RL17 1.42 fps per *
Hybrid 100v .78 fps per *
RL19 1.61 fps per *
VV N160 1.24 fps per *
Imr4831 1.19 fps per *
Ramshot Hunter .86 fps per *
H4831 .36 fps per *
RL22 1.71 fps per *
Imr7828 1.36 fps per *
Magpro 1.01 fps per *
H1000 .21 fps per *
RL25 1.59 fps per *
Ramshot Magnum .87 fps per *
Retumbo .49 fps per